1. Field of the Invention
The present invention relates in general to seat slide devices for sliding a seat in fore-and-aft directions to a desired position, and more particularly to seat slide devices of a type equipped with an anchor device of a seat belt.
2. Description of the Prior Art
In order to clarify the task of the present invention, one conventional seat slide device of the type as mentioned hereinabove will be described with reference to FIGS. 4 to 6 of the drawings.
Referring to FIG. 4, there is shown a vehicle cabin in which the conventional seat slide device 100 is arranged to support an assistant driver's seat 102. In the drawing, designated by numeral 104 is a vehicle body, and 104a is a floor panel of the body 104. The seat 102 comprises a seat cushion 106 mounted on the seat slide device 100 and a seat back 108 pivotally connected to the seat cushion 106 through a known reclining device.
As is seen from FIG. 4, the seat slide device 100 comprises generally two, that is, first and second slide units 100a and 100b which are arranged in parallel between the seat cushion 106 and the floor panel 104a.
As is understood from FIGS. 5 and 6, each slide unit 100a or 100b comprises a stationary rail 110 mounted through mounting brackets 112 (only one is shown) to the floor panel 104a, a movable rail 114 secured to the seat cushion 106 and slidably disposed on the stationary rail 110, and a position locker (not shown) for locking the movable rail 114 at a desired position relative to the stationary rail 110. As is seen from FIG. 6, the movable rail 114 is connected to a rectangular frame 106a of the seat cushion 106 through bolts 116 and nuts 118.
As is seen from FIGS. 5 and 6, an elongate stationary bracket 120 is secured to the bottom portion of the stationary rail 110 of the first slide unit 100a to extend along the same. The bracket 120 is formed at its outboard side with a channel-shaped portion 120a which extends therealong with the groove facing downward.
A generally L-shaped bracket 122 is secured at its horizontal portion to the rectangular frame 106a of the seat cushion 106 through the bolts 116 and the nuts 118. More specifically, the horizontal portion is tightly interposed between the frame 106a and the movable rail 114.
An anchor holding bracket 124 is welded to a vertical portion of the L-shaped bracket 122, so that the anchor holding bracket 124, the L-shaped bracket 122, the movable rail 114 and the seat cushion 106 can move together as a unit relative to the stationary rail 110 and the stationary bracket 120. The anchor holding bracket 124 is formed at its lower section with a channel-shaped portion 124a which is slidably engaged or interlocked with the channel-shaped portion 120a of the stationary bracket 120.
A belt anchor device 126 is pivotally connected, through a bolt 128 and a nut 130, to the anchor holding bracket 124. The belt anchor device 126 is equipped with a buckle 126a. Designated by numeral 132 in FIG. 5 is a part of the reclining device.
Upon rapid braking or the like, a considerable force is suddenly applied to the seat belt by the occupant on the seat 102. The force applied to the seat belt is thus transmitted to both the rectangular frame 106a of the seat cushion 106 and the movable rail 114 through the belt anchor device 124 and the L-shaped bracket 122. When, due to a vehicle collision or the like, a great impact force is applied to the seat belt and thus to the L-shaped bracket 122, the latter is forced to flex to such a degree that the channel-shaped portion 124a of the anchor holding bracket 124 is tightly interlocked with the channel-shaped portion 120a of the stationary bracket 120 thereby suppressing further flexing of the L-shaped bracket 122.
However, due to the inherent construction of the conventional seat slide device 100 as described hereinabove, the impact force transmitted to the rectangular frame 106a of the seat cushion 106 sometimes deforms the frame 106a. This is because the impact force applied to the seat belt is substantially directly transmitted to the rectangular frame 106a. Thus, when the frame 106a is constructed of thinner metal for the purpose of reducing the weight of the seat assembly, such undesirable deformation tends to occur.